Low-resistance contact to silicon having a titanium silicide interface and an amorphous titanium carbonitride barrier layer

ABSTRACT

A contact structure is provided incorporating an amorphous titanium nitride barrier layer formed via low-pressure chemical vapor deposition (LPCVD) utilizing tetrakis-dialkylamido-titanium, Ti(NMe 2 ) 4 , as the precursor. The contact structure is fabricated by etching a contact opening through a dielectric layer down to a diffusion region to which electrical contact is to be made. Titanium metal is deposited over the surface of the wafer so that the exposed surface of the diffusion region is completely covered by a layer of the metal. At least a portion of the titanium metal layer is eventually converted to titanium silicide, thus providing an excellent conductive interface at the surface of the diffusion region. A titanium nitride barrier layer is then deposited using the LPCVD process, coating the walls and floor of the contact opening. Chemical vapor deposition of polycrystalline silicon or of a metal follows.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 09/921,615,filed Aug. 3, 2001, now U.S. Pat. No. 6,632,736, issued Oct. 14, 2003,which is a continuation of application Ser. No. 09/495,534, filed Jan.31, 2000, now U.S. Pat. No. 6,291,340, issued Sep. 18, 2001, which is acontinuation of application Ser. No. 09/012,685, filed Jan. 23, 1998,now U.S. Pat. No. 6,081,034, issued Jun. 27, 2000, which is acontinuation of application Ser. No. 08/509,708, filed Jul. 31, 1995,now U.S. Pat. No. 5,723,382, issued Mar. 3, 1998, which is acontinuation-in-part of U.S. application Ser. No. 08/228,795, filed Apr.15, 1994, now abandoned, which is a continuation of now abandoned U.S.application Ser. No. 07/898,059, filed Jun. 12, 1992 now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to integrated circuit manufacturing technologyand, more specifically, to structures for making low-resistance contactthrough a dielectric layer to a diffusion region in an underlyingsilicon layer. The structures include an amorphous titanium nitridebarrier layer that is deposited via chemical vapor deposition.

2. State of the Art

The compound titanium nitride (TiN) has numerous potential applicationsbecause it is extremely hard, chemically inert (although it readilydissolves in hydrofluoric acid), an excellent conductor, possessesoptical characteristics similar to those of gold, and has a meltingpoint around 3000° C. This durable material has long been used to gildinexpensive jewelry and other art objects. However, during the last tento twelve years, important uses have been found for TiN in the field ofintegrated circuit manufacturing. Not only is TiN unaffected byintegrated circuit processing temperatures and most reagents, it alsofunctions as an excellent barrier against diffusion of dopants betweensemiconductor layers. In addition, TiN also makes excellent ohmiccontact with other conductive layers.

In a common application for integrated circuit manufacture, a contactopening is etched through an insulative layer down to a diffusion regionto which electrical contact is to be made. Titanium metal is thensputtered over the wafer so that the exposed surface of the diffusionregion is coated. The titanium metal is eventually converted to titaniumsilicide, thus providing an excellent conductive interface at thesurface of the diffusion region. A titanium nitride barrier layer isthen deposited, coating the walls and floor of the contact opening.Chemical vapor deposition of tungsten or polysilicon follows. In thecase of tungsten, the titanium nitride layer provides greatly improvedadhesion between the walls of the opening and the tungsten metal. In thecase of the polysilicon, the titanium nitride layer acts as a barrieragainst dopant diffusion from the polysilicon layer into the diffusionregion.

Titanium nitride films may be created using a variety of processes. Someof those processes are reactive sputtering of a titanium nitride target;annealing of an already deposited titanium layer in a nitrogen ambient;chemical vapor deposition at high temperature and at atmosphericpressure, using titanium tetrachloride, nitrogen and hydrogen asreactants; and chemical vapor deposition at low-temperature and atatmospheric pressure, using ammonia and Ti(NR₂)₄ compounds asprecursors. Each of these processes has its associated problems.

Both reactive sputtering and nitrogen ambient annealing of depositedtitanium result in films having poor step coverage, which are notuseable in submicron processes. Chemical vapor deposition (CVD)processes have an important advantage in that conformal layers of anythickness may be deposited. This is especially advantageous inultra-large-scale integrated circuits, where minimum feature widths maybe smaller than 0.5 μm. Layers as thin as 10 Å may be readily producedusing CVD. However, TiN coatings prepared using the high-temperatureatmospheric pressure CVD (APCVD) process must be prepared attemperatures between 900-1000° C. The high temperatures involved in thisprocess are incompatible with conventional integrated circuitmanufacturing processes. Hence, depositions using the APCVD process arerestricted to refractory substrates such as tungsten carbide. Thelow-temperature APCVD, on the other hand, though performed within atemperature range of 100-400° C. that is compatible with conventionalintegrated circuit manufacturing processes, is problematic because theprecursor compounds (ammonia and Ti(NR₂)₄) react spontaneously in thegas phase. Consequently, special precursor delivery systems are requiredto keep the gases separated during delivery to the reaction chamber. Inspite of special delivery systems, the highly spontaneous reaction makesfull wafer coverage difficult to achieve. Even when achieved, thedeposited films tend to lack uniform conformality, are generallycharacterized by poor step coverage, and tend to deposit on everysurface within the reaction chamber, leading to particle problems.

U.S. Pat. No. 3,807,008, which issued in 1974, suggested that tetrakisdimethylamino titanium, tetrakis diethylamino titanium, or tetrakisdiphenylamino titanium might be decomposed within a temperature range of400-1,200° C. to form a coating on titanium-containing substrates. Itappears that no experiments were performed to demonstrate the efficacyof the suggestion, nor were any process parameters specifically given.However, it appears that the suggested reaction was to be performed atatmospheric pressure.

In U.S. Pat. No. 5,178,911, issued to R. G. Gordon, et al., a chemicalvapor deposition process is disclosed for creating thin, crystallinetitanium nitride films using tetrakis-dimethylamido-titanium and ammoniaas precursors.

In the J. Appl. Phys. 70(7) October 1991, pp 3,666-3,677, A. Katz andcolleagues describe a rapid-thermal, low-pressure, chemical vapordeposition (RTLPCVD) process for depositing titanium nitride films,which, like those deposited by the process of Gordon, et al., arecrystalline in structure.

BRIEF SUMMARY OF THE INVENTION

This invention constitutes a contact structure incorporating anamorphous titanium nitride barrier layer formed via low-pressurechemical vapor deposition (LPCVD) utilizingtetrakis-dialkylamido-titanium, Ti(NMe₂)₄, as the precursor. Althoughthe barrier layer compound is primarily amorphous titanium nitride, itsstoichiometry is variable, and it may contain carbon impurities inamounts which are dependent on deposition and post-depositionconditions. The barrier layers so deposited demonstrate excellent stepcoverage, a high degree of conformality, and an acceptable level ofresistivity. Because of their amorphous structure (i.e., having nodefinite crystalline structure), the titanium nitride layer acts as anexceptional barrier to the migration of ions or atoms from a metal layeron one side of the titanium carbonitride barrier layer to asemiconductor layer on the other side thereof, or as a barrier to themigration of dopants between two different semiconductor layers whichare physically separated by the barrier layer.

The contact structure is fabricated by etching a contact opening througha dielectric layer down to a diffusion region to which electricalcontact is to be made. Titanium metal is deposited over the surface ofthe wafer so that the exposed surface of the diffusion region iscompletely covered by a layer of the metal. Sputtering is the mostcommonly utilized method of titanium deposition. At least a portion ofthe titanium metal layer is eventually converted to titanium silicide,thus providing an excellent conductive interface at the surface of thediffusion region. A titanium nitride barrier layer is then depositedusing a low-pressure chemical vapor deposition (LPCVD) process, coatingthe walls and floor of the contact opening. Chemical vapor deposition(CVD) of polycrystalline silicon, or of a metal, such as tungsten,follows, and proceeds until the contact opening is completely filledwith either polycrystalline silicon or the metal. In the case of thepolysilicon, which must be doped with N-type or P-type impurities torender it conductive, the titanium nitride layer acts as a barrieragainst dopant diffusion from the polysilicon layer into the diffusionregion. In the case of CVD tungsten, the titanium nitride layer protectsthe junction from reactions with precursor gases during the CVDdeposition process, provides greatly improved adhesion between the wallsof the opening and the tungsten metal, and prevents the diffusion oftungsten atoms into the diffusion region.

Deposition of the titanium nitride barrier layer takes place in alow-pressure chamber (i.e., a chamber in which pressure has been reducedto less than 100 torr prior to deposition), and utilizes a metal-organictetrakis-dialkylamido-titanium compound as the sole precursor. Any noblegas, as well as nitrogen or hydrogen, or a mixture of two or more of theforegoing, may be used as a carrier for the precursor. The wafer isheated to a temperature within a range of 200-600° C. Precursormolecules which contact the heated wafer are pyrolyzed to form titaniumnitride containing variable amounts of carbon impurities, which depositsas a highly conformal film on the wafer.

The carbon content of the barrier film may be minimized by utilizingtetrakis-dimethylamido-titanium, Ti(NMe₂)₄, as the precursor, ratherthan compounds such as tetrakis-diethylamido-titanium ortetrakis-dibutylamido-titanium, which contain a higher percentage ofcarbon by weight. The carbon content of the barrier film may be furtherminimized by performing a rapid thermal anneal step in the presence ofammonia.

The basic deposition process may be enhanced to further reduce thecarbon content of the deposited titanium nitride film by introducing oneor more halogen gases, or one or more activated species (which mayinclude halogen, NH₃, or hydrogen radicals) into the deposition chamber.Halogen gases and activated species attack the alkyl-nitrogen bonds ofthe primary precursor and convert displaced alkyl groups into volatilecompounds.

As heretofore stated, the titanium carbonitride films formed by theinstant chemical vapor deposition process are principally amorphouscompounds. Other processes currently in use for depositing titaniumnitride-containing compounds as barrier layers within integratedcircuits result in titanium nitride having crystalline structures. Asatomic and ionic migration tends to occur at crystal grain boundaries,an amorphous film is a superior barrier to such migration.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block schematic diagram of a low-pressure chemical vapordeposition reactor system;

FIG. 2 is an X-ray spectrum (i.e., a plot of counts per second as afunction of 2-theta);

FIG. 3 is a cross-sectional view of a contact opening having a narrowaspect ratio that has been etched through an insulative layer to anunderlying silicon substrate, the insulative layer and the contactopening having been subjected to a blanket deposition of titanium metal;

FIG. 4 is a cross-sectional view of the contact opening of FIG. 3following the deposition of an amorphous titanium nitride film;

FIG. 5 is a cross-sectional view of the contact opening of FIG. 4following an anneal step; and

FIG. 6 is a cross-sectional view of the contact opening of FIG. 5following the deposition of a conductive material layer.

DETAILED DESCRIPTION OF THE INVENTION

The integrated circuit contact structure that is the focus of thisdisclosure is unique because of the use of a predominantly amorphoustitanium or titanium carbonitride barrier layer therein. The layer isdeposited using a low-pressure chemical vapor deposition (LPCVD) processthat is the subject of previously filed U.S. patent applications asheretofore noted.

The LPCVD process for depositing highly conformal titanium nitride andtitanium carbonitride barrier films will now be briefly described inreference to the low-pressure chemical vapor deposition reactor systemdepicted in FIG. 1. The deposition process takes place in a cold wallchamber 11. A wafer 12, on which the deposition will be performed, ismounted on a susceptor plate 13, which is heated to a temperature withina range of 200-600° C. by a heat lamp array 14. For the instant process,a carrier gas selected from a group consisting of the noble gases andnitrogen and hydrogen is bubbled through liquidtetrakis-dialkylamido-titanium 15 (the sole metal-organic precursorcompound) in a bubbler apparatus 16.

It should be noted that tetrakis-dialkylamido-titanium is a family ofcompounds, of which tetrakis-dimethylamido-titanium,tetrakis-diethylamido-titanium and tetrakis-dibutylamido-titanium havebeen synthesized. Because of its lower carbon content per unit ofmolecular weight, tetrakis-dimethylamido-titanium is the preferredprecursor because it results in barrier films having lower carboncontent. However, any of the three compounds or any combination of thethree compounds will result in highly conformal barrier layers whenpyrolyzed (decomposition by heating) in a CVD deposition chamber. Thesebarrier layers are characterized by an amorphous structure, and by stepcoverage on vertical wall portions near the base of submicron contactopenings having depth-to-width aspect ratios of 3:1 that range from80-90 percent of the horizontal film thickness at the top of theopening.

Still referring to FIG. 1, the carrier gas, at least partially saturatedwith a vaporized precursor compound, is transported via a primary intakemanifold 17 to a premix chamber 18. Additional carrier gas may beoptionally supplied to premix chamber 18 via supply tube 19. Carriergas, mixed with the precursor compound, is then ducted through asecondary intake manifold 20 to a shower head 21, from which they enterthe chamber 11. The precursor compound, upon coming into contact withthe heated wafer, pyrolyzes and deposits as a highly conformal titaniumcarbonitride film on the surface of the wafer 12. The reaction productsfrom the pyrolysis of the precursor compound are withdrawn from thechamber 11 via an exhaust manifold 22. Incorporated in the exhaustmanifold 22 are a pressure sensor 23, a pressure switch 24, a vacuumvalve 25, a pressure control valve 26, a blower 27, and a particulatefilter 28, which filters out solid reactants before the exhaust isvented to the atmosphere. During the deposition process, the pressurewithin chamber 11 is maintained at a pressure of less than 100 torr andat a pressure of less than 1 torr by pressure control components 23, 24,25, 26, and 27. The process parameters that are presently deemed to beoptimum, or nearly so, are a carrier gas flow through secondary intakemanifold 20 of 400 standard cubic centimeters per minute (scc/m), adeposition chamber temperature of 425° C., and a flow of carrier gasthrough bubbler apparatus 16 of 100 scc/m, with the liquidtetrakis-dialkylamido-titanium 15 being maintained at a constanttemperature of approximately 40° C.

Thus, the carrier gas (or gases) and the vaporized precursor compoundare then gradually admitted into the chamber until the desired pressureand gas composition is achieved. The reaction, therefore, takes place ata constant temperature, but with varying gas partial pressures duringthe initial phase of the process. This combination of process parametersis apparently responsible for the deposition of titanium carbonitridehaving a predominantly amorphous structure as the precursor compoundundergoes thermal decomposition. The X-ray spectrum of FIG. 2 isindicative of such an amorphous structure. Both the peak at a 2-thetavalue of 36, which is characteristic of titanium nitride having a (111)crystal orientation, and the peak at a 2-theta value of 41, which ischaracteristic of titanium nitride having a (200) crystal orientation,are conspicuously absent from the spectrum. Such a spectrum indicatesthat there is virtually no crystalline titanium nitride in the analyzedfilm. Incidentally, the peak at a 2-theta value of 69 is representativeof silicon.

Although the compound deposited on the wafer with this process may bereferred to as titanium carbonitride (represented by the chemicalformula TiC_(x)N_(y)), the stoichiometry of the compound is variable,depending on the conditions under which it is deposited. The primaryconstituents of films deposited using the new process andtetrakis-dimethylamido-titanium as the precursor are titanium andnitrogen, with the ratio of nitrogen atoms to carbon atoms in the filmfalling within a range of 5:1 to 10:1. In addition, upon exposure to theatmosphere, the deposited films absorb oxygen. Thus the final film maybe represented by the chemical formula TiC_(x)N_(y)O_(z). The carbon andoxygen impurities affect the characteristics of the film in at least twoways. Firstly, the barrier function of the film is enhanced. Secondly,the carbon and oxygen impurities dramatically raise the resistivity ofthe film. Sputtered titanium nitride has a bulk sheet resistivity ofapproximately 75 μohm-cm, while the titanium carbonitride filmsdeposited through the CVD process disclosed herein have bulk sheetresistivities of 2,000 to 50,000 μohm-cm. In spite of this dramaticincrease in bulk resistivity, the utility of such films as barrierlayers is largely unaffected, due to the characteristic thinness ofbarrier layers used in integrated circuit manufacture. A simple analysisof the contact geometry for calculating various contributions to theoverall resistance suggests that metal (e.g., tungsten) plug resistanceand metal-to-silicon interface resistance play a much more significantrole in overall contact resistance than does the barrier layer.

There are a number of ways by which the basic LPCVD process may beenhanced to minimize the carbon content of the deposited barrier film.

The simplest way is to perform a rapid thermal anneal step in thepresence of ammonia. During such a step, much of the carbon in thedeposited film is displaced by nitrogen atoms.

The basic deposition process may be enhanced to further reduce thecarbon content of the deposited titanium nitride film by introducing anactivated species into the deposition chamber. The activated speciesattacks the alkyl-nitrogen bonds of the primary precursor and convertsdisplaced alkyl groups into volatile compounds. The activated species,which may include halogen, NH₃, or hydrogen radicals, or a combinationthereof, are generated in the absence of the primary precursor at alocation remote from the deposition chamber. Remote generation of theactivated species is required because it is not desirable to employ aplasma CVD process, as Ti(NR₂)₄ is known to break down in plasma,resulting in large amounts of carbon in the deposited film. A highcarbon content will elevate the bulk resistivity of the film to levelsthat are unacceptable for most integrated circuit applications. Theprimary precursor molecules and the activated species are mixed,preferably, just prior to being ducted into the deposition chamber. Itis hypothesized that as soon as the mixing has occurred, the activatedspecies begin to tear away the alkyl groups from the primary precursormolecules. Relatively uncontaminated titanium nitride deposits on theheated wafer surface.

Alternatively, the basic deposition process may be enhanced to lower thecarbon content of the deposited titanium nitride films by introducing ahalogen gas, such as F₂, Cl₂ or Br₂, into the deposition chamber. Thehalogen gas molecule attacks the alkyl-nitrogen bonds of the primaryprecursor compound molecule and converts the displaced alkyl groups intoa volatile compound. The halogen gas is admitted to the depositionchamber in one of three ways. The first way is to admit halogen gas intothe deposition chamber before the primary precursor compound isadmitted. During this “pre-conditioning” step, the halogen gas becomesadsorbed on the chamber and wafer surfaces. The LPCVD deposition processis then performed without admitting additional halogen gas into thedeposition chamber. As a first alternative, the halogen gas andvaporized primary precursor compound are admitted into the depositionchamber simultaneously. Ideally, the halogen gas and vaporized primaryprecursor compound are introduced into the chamber via a single showerhead having separate ducts for both the halogen gas and the vaporizedprimary precursor compound. Maintaining the halogen gas separate fromthe primary precursor compound until it has entered the depositionchamber prevents the deposition of titanium nitride on the shower head.It is hypothesized that as soon as the mixing has occurred, the halogenmolecules attack the primary precursor molecules and begin to tear awaythe alkyl groups therefrom. Relatively uncontaminated titanium nitridedeposits on the heated wafer surface. As a second alternative, halogengas is admitted into the chamber both before and during the introductionof the primary precursor compound.

As heretofore stated, the titanium nitride or titanium carbonitridefilms deposited by the described LPCVD process are predominantlyamorphous compounds. Other processes currently in use for depositingtitanium nitride-containing compounds as barrier layers withinintegrated circuits result in titanium nitride having crystallinestructures. As atomic and ionic migration tends to occur at crystalgrain boundaries, an amorphous film is a superior barrier to suchmigration.

Referring now to FIG. 3, which is but a tiny cross-sectional area of asilicon wafer undergoing an integrated circuit fabrication process, acontact opening 31 having a narrow aspect ratio has been etched througha borophosphosilicate glass (BPSG) layer 32 to a diffusion region 33 inan underlying silicon substrate 34. A titanium metal layer 35 is thendeposited over the surface of the wafer. Because titanium metal isnormally deposited by sputtering, it deposits primarily on horizontalsurfaces. Thus, the portions of the titanium metal layer 35 on the wallsand at the bottom of the contact opening 31 are much thinner than theportion that is outside of the opening on horizontal surfaces. Theportion of titanium metal layer 35 that covers diffusion region 33 atthe bottom of contact opening 31 will be denoted 35A. At least a portionof the titanium metal layer portion 35A will be converted to titaniumsilicide in order to provide a low-resistance interface at the surfaceof the diffusion region.

Referring now to FIG. 4, a titanium nitride barrier layer 41 is thendeposited utilizing the LPCVD process, coating the walls and floor ofthe contact opening 31.

Referring now to FIG. 5, a high-temperature anneal step in an ambientgas such as nitrogen, argon, ammonia, or hydrogen is performed eitherafter the deposition of the titanium metal layer 35 or after thedeposition of the titanium nitride barrier layer 41. Rapid thermalprocessing (RTP) and furnace annealing are two viable options for thisstep. During the anneal step, the titanium metal layer portion 35A atthe bottom of contact opening 31 is either partially or completelyconsumed by reaction with a portion of the upper surface of thediffusion region 33 to form a titanium silicide layer 51. The titaniumsilicide layer 51, which forms at the interface between the diffusionregion 33 and titanium metal layer portion 35A, greatly lowers contactresistance in the contact region.

Referring now to FIG. 6, a low-resistance conductive layer 62 of metalor heavily-doped polysilicon may be deposited on top of the titaniumnitride barrier layer 41. Tungsten or aluminum metal is commonly usedfor such applications. Copper or nickel, though more difficult to etchthan aluminum or tungsten, may also be used.

Although only several embodiments of the inventive process have beendisclosed herein, it will be obvious to those having ordinary skill inthe art that modifications and changes may be made thereto withoutaffecting the scope and spirit of the invention as claimed.

1. A process for fabricating a contact structure for an integratedsemiconductor circuit comprising: providing a silicon region on at leasta portion of a surface of a semiconductor wafer for making electricalcontact thereto; depositing a dielectric layer over the silicon region;etching a contact opening through the dielectric layer for exposing aportion of the silicon region, the contact opening having a sidewall;depositing a titanium metal layer within the contact opening to coverthe portion of the silicon region exposed by the contact opening;depositing an amorphous titanium carbonitride film having substantiallyno crystalline titanium therein, the amorphous titanium carbonitridefilm lining the sidewall of the contact opening and overlaying thetitanium metal layer covering the portion of the silicon region exposedby the contact opening using a vapor deposition process when thesemiconductor wafer is located in a chamber; and filling at least aportion of the contact opening using a conductive material.
 2. Theprocess of claim 1, wherein depositing the amorphous titaniumcarbonitride film includes a chemical vapor deposition process.
 3. Theprocess of claim 2, wherein the chemical vapor deposition processincludes: evacuating a deposition chamber to a pressure of less thanabout 100 torr; heating the semiconductor wafer to a temperature withina range of about 200° to about 600° C.; maintaining the temperature ofthe semiconductor wafer; admitting an organometallic precursor compoundinto the deposition chamber, the organometallic precursor compoundincluding a tetrakis-dialkylamido-titanium compound; decomposing theorganometallic precursor compound at or near the surface of thesemiconductor wafer; and depositing the amorphous titanium carbonitridefilm having substantially no crystalline titanium therein on at least aportion of the surface of the semiconductor wafer and within the contactopening.
 4. The process of claim 3, wherein the organometallic precursorcompound comprises tetrakis-dimethylamido-titanium.
 5. The process ofclaim 1, wherein the conductive material comprises a metal selected fromthe group consisting of tungsten, aluminum, copper and nickel.
 6. Theprocess of claim 1, wherein the conductive material comprises dopedpolycrystalline silicon.
 7. The process of claim 1, further comprising:heating the semiconductor wafer; and reacting at least a portion of thetitanium metal layer covering the portion of the silicon region exposedby the contact opening with the silicon region to form a titaniumsilicide layer.
 8. The process of claim 7, wherein reacting the at leasta portion of the titanium metal layer with the silicon region occursprior to depositing the amorphous titanium carbonitride film havingsubstantially no crystalline titanium therein.
 9. The process of claim7, wherein reacting the at least a portion of the titanium metal layerwith the silicon region occurs subsequent to depositing the amorphoustitanium carbonitride film having substantially no crystalline titaniumtherein.
 10. The process of claim 1, further comprising: subjecting theamorphous titanium carbonitride film having substantially no crystallinetitanium therein to rapid thermal processing in the presence of one ormore gases selected from the group consisting of nitrogen, hydrogen andthe noble gases.
 11. An integrated circuit fabrication process for acontact structure comprising: providing a silicon region on at least aportion of a surface of a semiconductor wafer for making electricalcontact thereto; depositing a dielectric layer over the silicon region;etching a contact opening through the dielectric layer for exposing aportion of the silicon region, the contact opening having a sidewall;depositing a titanium metal layer within the contact opening to coverthe portion of the silicon region exposed by the contact opening;depositing an amorphous titanium carbonitride film having substantiallyno crystalline titanium therein, the amorphous titanium carbonitridefilm lining the sidewall of the contact opening and overlaying thetitanium metal layer covering the portion of the silicon region exposedby the contact opening using a vapor deposition process when thesemiconductor wafer is located in a chamber; and filling at least aportion of the contact opening using a conductive material.
 12. Theprocess of claim 11, wherein depositing the amorphous titaniumcarbonitride film includes a chemical vapor deposition process.
 13. Theprocess of claim 12, wherein the chemical vapor deposition processincludes: evacuating a deposition chamber to a pressure of less thanabout 100 torr; heating the semiconductor wafer to a temperature withina range of about 200° to about 600° C.; maintaining the temperature ofthe semiconductor wafer; admitting an organometallic precursor compoundinto the deposition chamber, the organometallic precursor compoundincluding a tetrakis-dialkylamido-titanium compound; decomposing theorganometallic precursor compound at or near the surface of thesemiconductor wafer; and depositing the amorphous titanium carbonitridefilm having substantially no crystalline titanium therein on at least aportion of the surface of the semiconductor wafer and within the contactopening.
 14. The process of claim 13, wherein the organometallicprecursor compound comprises tetrakis-dimethylamido-titanium.
 15. Theprocess of claim 11, wherein the conductive material comprises a metalselected from the group consisting of tungsten, aluminum, copper andnickel.
 16. The process of claim 11, wherein the conductive materialcomprises doped polycrystalline silicon.
 17. The process of claim 11,further comprising: heating the semiconductor wafer; and reacting atleast a portion of the titanium metal layer covering the portion of thesilicon region exposed by the contact opening with the silicon region toform a titanium silicide layer.
 18. The process of claim 17, whereinreacting the at least a portion of the titanium metal layer with thesilicon region occurs prior to depositing the amorphous titaniumcarbonitride film having substantially no crystalline titanium therein.19. The process of claim 17, wherein reacting the at least a portion ofthe titanium metal layer with the silicon region occurs subsequent todepositing the amorphous titanium carbonitride film having substantiallyno crystalline titanium therein.
 20. The process of claim 11, furthercomprising: subjecting the amorphous titanium carbonitride film havingsubstantially no crystalline titanium therein to rapid thermalprocessing in the presence of one or more gases selected from the groupconsisting of nitrogen, hydrogen and the noble gases.